How to make this part?

Hi all I was hopeing some one could help me

I am modelling a glock 19 and I have made the slide part and so far it looks good but I am struggling with the lower part mainly the grip section.

Would I be best to model the bottom half as a seprate part?

this is the gun in question

http://www.justpistols.co.uk/kwa19_001.jpg

Thanks for your time

SolidworksSketching